5-132
F codes
E codes
C codes
P codes
H codes
A codes
b codes
r codes
J codes
d codes
U codes
y codes
Chap. 5 FUNCTION CODES
Operation examples
Servo-lockNot defined
OFF ON
Speed control
ON
ON
OFF
OFF
LOCK
Control status
Gate
Stop frequency (F25)
Servo-lock Not defined
OFF
Detected speed (F38=0)
Reference speed (F38=1)
OFF
FWD/REV
Typical Control Sequence of Servo-lock
When the servo-lock command is ON, the inverter keeps on outputting voltage on output terminals [U], [V] and [W]
even if a run command is OFF and the motor seems to stop.
An electric shock may occur.
Specifying servo-lock control
■ Positioning completion signal -- PSET (Function code data = 82), Servo-lock (Completion timer) (J98),
and Servo-lock (Completion range) (J99)
This output signal comes ON when the inverter has been servo-locked so that the motor is held within the positioning
completion range specified by J99 for the period specified by J98.
■ Servo-lock (Gain) (J97)
J97 specifies the gain of the servo-lock positioning device to adjust the stop behavior and shaft holding torque.
J97 Small
↔ Large
Stop behavior Response slow, but smooth ↔ Response quick, but hunting large
Shaft holding torque Small ↔ Large
Monitor for servo-lock control
Monitor item LED monitor Function code Remarks
Current position
Operation monitor:
3_26
The upper and lower digits
appear alternately.
Current position pulse
Upper digit: Z90
Lower digit: Z91
Positioning error
Operation monitor:
3_28
The upper and lower digits
appear alternately.
Positioning error pulse
Upper digit: Z94
Lower digit: Z95
Only when the positioning device is
in operation (positioning control is
active), the LED monitor displays
these data. When it is not in
operation, the monitor is
zero-cleared.
The values on the LED monitor appear based on PG pulses 4-multiplied. Under servo-lock, no current positioning
pulses or positioning error pulses are displayed on the LED monitor.
Notes for using servo-lock
(1) Positioning control error
ero
If a positioning error exceeds the value equivalent to four rotations of the motor shaft when the inverter is
servo-locked, the inverter issues a positioning control error signal
ero
.
(2) Stop frequency (F25) under servo-lock
Since servo-lock starts when the output frequency is below the stop frequency (F25), it is necessary to specify such
F25 data that does not trigger
ero
(that is, specify the value equivalent to less than 4 rotations of the motor shaft).
Stop frequency (F25) < (4 × Gain (J97) × Maximum frequency)
(Example) When Gain (J97) = 0.01 and Maximum frequency (F03) = 60 Hz, specify F25 data < 2.4 Hz.
(3) Enabling the servo-lock control disables the following:
• Operation controlled with a stop frequency
• Rotation direction limitation
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